Kanser Tanısında Kullanılmak Üzere Yeni Nesil Kolorimetrik Biyosensörlerin Geliştirilmesi
Özet
Breast cancer is the most common type of cancer among women. Today, breast cancer diagnosis is determined by techniques requiring expert analysis, difficult to carry, expensive, and time-consuming, and the need for specific and hypersensitive new devices is increasing. Early diagnosis of cancer is crucial for patient survival and the success of the treatment. With biosensor technology in cancer diagnosis, many researchers have turned to improving low-cost, fast, convenient biosensors that can be used at the point of care.
In this thesis, a new generation colorimetric biosensor was designed for the diagnosis of breast cancer. Glass capillary tubes, which are helpful for optical-immuno-sensing, were chosen as sensor platform. Glass surfaces are functionalized with amine by using two different methods in liquid and gas phase. Glass surfaces were analyzed with XPS. It was determined that the amination process in gas phase was more effective. The effect of pressure and APTES concentration on amination was examined for gas-phase amination. It was determined that the best amination was achieved with 50 μl APTES under 0.06 Mpa pressure.
Human epidermal growth factor receptor-2 (HER-2) and cancer antigen 15-3 (CA15-3) breast cancer antibodies were used as the biological sensing element. Detection antibodies activated by the oxidation process were immobilized on glass surfaces functionalized with amine. HER-2 and CA15-3 antigens and SK-BR-3 HER2(+) breast cancer cells were used as markers.
Gold nanoparticles (AuNP) with unique optical properties have been preferred as signal transmitters to detect and visualize breast cancer markers in colorimetric biosensor. AuNPs synthesized by the chemical method modified were coated with MUA to form specific recognition and binding sites and made into a monolayer. AuNPs were characterized using various techniques such as Zeta-Sizer, UV-VIS, FTIR, TEM, and 25 nm AuNPs were obtained. The synthesized AuNPs were treated with capturing antibodies and the antibodies were conjugated to the AuNP surface.
The glass capillary-based colorimetric biosensor was validated using detection antibody cancer antigen, and capture antibody coated AuNPs. The biosensor was optimized by examining the effects of different parameters such as antigen concentration, incubation time, the amount of detection antibody, and capture antibody coated with AuNPs on immobilization. The immobilization on glass surface was characterized by FTIR and was confirmed by the appearance of -NH peaks and amide bands.
The validation results of the designed colorimetric biosensor were viewed with the naked eye and under a microscope without the need for any device. The immobilization which breast cancer biomarkers (HER-2 and CA15-3), and HER2(+) cells was detected by the colored layering on the glass surfaces. The resulting color formations confirmed the working efficiency of the new generation colorimetric biosensor designed for breast cancer diagnosis. The features of designed biosensor, such as its portable size, easy application, and obtaining results without an expert, will make a significant contribution to the screening tests to be designed for cancer diagnosis in the future.
We hope that this study will be helpful in the development of new generation biosensors with a simple, easy-to-use, cost-effective and applicable approach for cancer diagnosis.
